CPR training system and method

ABSTRACT

A training system and training method for cardiopulmonary resuscitation (CPR) is disclosed. The training system includes a manikin, a chest compression module, a breathing module and a data processing module. The chest compression module and the breathing module are installed on the manikin and connected to the data processing module. During a training session, a student performs CPR on the manikin. The data processing module evaluates and provides feedback regarding the chest compressions and the rescue breathings performed by the student. The training method includes positioning the chest compression module and the breathing module on the manikin, initializing the chest compression module and the breathing module to identify compression and breathing characteristics of the manikin, performing CPR on the manikin, and evaluating the CPR based on the compression and breathing characteristics of the manikin.

BACKGROUND

The present disclosure relates to a training system and method forcardiopulmonary resuscitation (CPR). CPR is a lifesaving techniqueuseful in emergency situations when a person is not breathing and has nopulse. CPR supplies life-sustaining oxygen to the brain and other vitalorgans until emergency medical responders arrive. CPR training isessential to ensure that the lifesaving technique is safely andeffectively performed. CPR training systems and methods use humanmanikins.

SUMMARY

One aspect of the invention provides a method for a CPR training. Themethod comprises one or more of the following steps:

-   -   providing a manikin comprising an interior structure and a        removable skin fitted over the interior structure, the interior        structure comprising a frame corresponding a rib cage of a human        body;    -   providing a compression pad comprising a housing, at least one        force sensor, at least one acceleration sensor housed within the        housing, at least one force sensors configured to detect force        applied thereto, the at least one acceleration sensor configured        to detect acceleration applied thereto;    -   lifting or removing the skin to expose at least part of the        frame;    -   subsequently placing a compression pad over the frame;    -   subsequently fitting the skin over the interior structure such        that the compression pad is located in the manikin's chest        region under the skin;    -   performing a sequence of initializing compressions onto the        manikin's chest region, which applies force and acceleration        that the at least one force sensor and the at least one        acceleration sensor can detect respectively;    -   providing initializing force signals generated by the at least        one force sensor and initializing acceleration signals generated        by the at least one acceleration sensor in response to the        initializing compressions;    -   processing the initializing acceleration signals to generate        initializing displacement signals representing displacement of        the compression pad caused by the initializing compressions;    -   processing the initializing force signals and the initializing        displacement signals to provide a correlation between        displacement of the compression pad and force applied to the        compression pad by the initializing compressions;    -   subsequently, performing a CPR training session comprising a        sequence of training compressions onto the manikin's chest        region, which applies force and acceleration that the at least        one force sensor and the at least one acceleration sensor can        detect respectively;    -   providing training force signals generated by the at least one        force sensor in response to the training compressions; and    -   computing displacement caused by the training compressions using        the training force signals and the correlation between        displacement and force by the initializing compressions, wherein        computing displacement does not use acceleration caused by the        training compressions.

The above-described method further comprises one or more the followingfeatures:

-   -   wherein the at least one force sensor comprises a first force        sensor and a second force sensor that are apart from each other        within the housing,    -   wherein the first and second force sensors are configured to        generate their one force signals which are processed to provide        the force signals of the at least one force sensor,    -   wherein the compression pad comprises a first pressing plate and        a first support plate between which the first force sensor is        sandwiched, and    -   wherein the first pressing plate comprises a raised portion        raised toward the first force sensor and configured to contact        the first force sensor in response to compressions applied to        the compression pad.

In the above-described methods, the compression pad further comprises:

-   -   a printed circuit board (PCB) enclosed within the housing;    -   a plurality of contact sensors comprising a first element and a        second element;    -   the first element comprising a plurality of contact patches        provided on an inner surface of the housing, wherein the        plurality of contact patches are made of an electrically        conductive material and are not electrically connected to each        other; and    -   the second element comprising one or more sets of contact        patterns formed on the PCB, wherein the contact patterns in each        set comprises two or more electrically separate conductive        patterns in close proximity with each other and exposed toward        at least part of the plurality of contact patches.

The above-described methods further comprise one or more the followingfeatures:

-   -   wherein the plurality of contact patches are arranged on the        inner surface of the housing and the contact patterns are        arranged on the PCB such that each contact patch faces a        corresponding set of contact patterns while the contact patch        does not contact its corresponding set of contact patterns when        no external force or compression is applied to the housing, and    -   wherein the apparatus is configured to generate contact signals        when at least one of the contact patches contacts its        corresponding set of contact patterns in response to external        force or compression applied onto the housing.

The above-described methods further comprise one or more the followingfeatures:

-   -   presenting the computed displacement to a user performing the        CPR training session real time, and    -   wherein providing training force signals and computing        displacement are performed real time while the training        compressions are conducted such that a displacement value is        obtained for each compression before the next compression is        performed onto the manikin.

The above-described methods further comprise one or more the followingfeatures:

-   -   comparing the computed displacement against a predetermined        range of compression depth to determine whether each compression        of the CPR training session satisfies a compression depth        requirement; and    -   presenting a result of determination real time before the user        performs the next compression onto the manikin.

The above-described methods further comprise one or more the followingfeatures:

-   -   providing a breathing module comprising a lung bag and an air        pressure sensor connected to the lung bag such that the air        pressure sensor can detect air pressure within the lung bag;    -   connecting the lung bag with a breathing cavity of the manikin        such that the breathing cavity of the manikin and the lung bag        are in fluid communication therebetween;    -   placing the lung bag over the compression pad after placing the        compression pad over the manikin's frame and before fitting the        skin over the interior structure;    -   performing a sequence of initializing breathings via the        breathing cavity of the manikin, which blows air into the lung        bag that the air pressure sensor can detect;    -   providing initializing air pressure signals generated by the air        pressure sensor in response to the initializing breathings;    -   providing volume information of the initializing breathings;    -   processing the initializing air pressure signals and the volume        information to provide a correlation between volume of the        initializing breathings and air pressure within the lung bag        caused by the initializing breathings;    -   subsequently, performing the CPR training session further        comprising at least one training breathing via the manikin's        breathing cavity, which blows air into the lung bag that the air        pressure sensor can detect;    -   providing training air pressure signals generated by the air        pressure sensor in response to the at least one training        breathing; and    -   computing volume caused by the training breathing using the        training air pressure signals and the correlation between volume        and air pressure by the initializing breathings, wherein volume        is not detected for the at least one training breathing.

The above-described methods further comprise one or more the followingfeatures:

-   -   wherein the CPR training session comprises the sequence of        training compressions and the at least one training breathing        that are repeated multiple times,    -   wherein the method further comprises: confirming a compression        when the force signal or its corresponding displacement signal        is greater than a predetermined compression threshold, and        confirming a breathing when the air pressure or its        corresponding volume is greater than a predetermined breathing        threshold.

In the above-described methods, the CPR training session involves afirst instance in which the air pressure sensor generates an airpressure signal greater than the predetermined breathing threshold inresponse to performing the training compressions even if no breathing isperformed at the same time.

In the above-described methods, the CPR training session involves asecond instance in which the force sensor generates force signalsgreater than the predetermined compression threshold in response toperforming the at least one training breathing even if no compression isperformed at the same time.

In the above-described methods, in the first or second instance, themethod determines that the user has performed a compression or abreathing in view of an immediately previous user action of compressionor breathing that has been confirmed.

In the above-described methods, in the first or second instance, themethod determines that the user has performed a compression regardlessof the air pressure signal.

In the above-described methods, in the first or second instance, themethod determines that the user has performed a compression if the timetaken from the immediately previous confirmed user action of compressionor breathing is shorter than a predetennined reference time, wherein themethod determines the user has performed a breathing, if the time takenfrom the immediately previous confirmed user action of compression orbreathing is longer than a predetermined reference time.

In the above-described methods, in the first or second instance, themethod determines that the user has performed a compression or abreathing in view of the number of immediately previous consecutivecompressions of the user and further in view of the required number ofconsecutive compressions of the CPR training session such that if thenumber of immediately previous consecutive compressions of the user issmaller than the required number of the CPR training session, it isdetermined that the user has performed another compression.

The above-described methods further comprise one or more the followingfeatures:

-   -   connecting the lung bag with a breathing cavity of the manikin        such that the breathing cavity of the manikin and the lung bag        are in fluid communication therebetween;    -   performing a sequence of initializing breathings via the        breathing cavity of the manikin, which blows air into the lung        bag that the air pressure sensor can detect;    -   providing initializing air pressure signals generated by the air        pressure sensor in response to the initializing breathings;    -   providing volume information of the initializing breathings;    -   processing the initializing air pressure signals and the volume        information to provide a correlation between volume of the        initializing breathings and air pressure within the lung bag        caused by the initializing breathings;    -   subsequently, performing the CPR training session further        comprising at least one training breathing via the manikin's        breathing cavity, which blows air into the lung bag that the air        pressure sensor can detect;    -   providing training air pressure signals generated by the air        pressure sensor in response to the training breathing; and    -   computing volume caused by the training breathing using the at        least one training air pressure signals and the correlation        between volume and air pressure by the initializing breathings,        wherein volume is not detected for the at least one training        breathing.

Another aspect of the invention provides a compression pad apparatus forCPR training. The apparatus comprises one or more of the followingfeatures:

-   -   a housing comprising an interior surface;    -   a printed circuit board (PCB) enclosed within the housing;    -   at least one force sensor configured to detect force;    -   a plurality of contact sensors comprising a first element and a        second element;    -   the first element comprising a plurality of contact patches        provided on the inner surface, wherein the plurality of contact        patches are made of an electrically conductive material and are        not electrically connected to each other;    -   the second element comprising one or more sets of contact        patterns formed on the PCB, wherein the contact patterns in each        set comprises two or more electrically separate conductive        patterns in close proximity with each other and exposed toward        at least part of the plurality of contact patches;    -   wherein the plurality of contact patches are arranged on the        inner surface of the housing and the contact patterns are        arranged on the PCB such that each contact patch faces a        corresponding set of contact patterns while the contact patch        does not contact its corresponding set of contact patterns when        no external force or compression is applied to the housing; and    -   wherein the apparatus is configured to generate contact signals        when at least one of the contact patches contacts its        corresponding set of contact patterns in response to external        force or compression applied onto the housing.

The above-described apparatus further comprises one or more of thefollowing features:

-   -   wherein the housing comprises a plurality of recesses formed        into the interior surface for accommodating the plurality of        contact patches, and    -   wherein each contact patch is inserted in one of the plurality        of recesses such that a top surface of the contact patch        inserted into the recess is at a level lower than the interior        surface to ensure that the top surface of the contact patch does        not contact its corresponding set of contact patterns formed on        the PCB when the apparatus is operably assembled.

Another aspect of the invention provides a method for a CPR training.The method comprises one or more of the following features:

-   -   providing a manikin comprising an interior structure and a        removable skin fitted over the interior structure, the interior        structure comprising a frame corresponding a rib cage of a human        body;    -   providing a compression pad comprising a housing and a plurality        of contact sensors that are housed within the housing;    -   lifting or removing the skin to expose at least part of the        frame;    -   subsequently placing a compression pad over the frame;    -   subsequently fitting the skin over the interior structure such        that the compression pad is located in the manikin's chest        region under the skin;    -   detecting at least one location of compression applied onto the        compression pad when a CPR training session comprising a chest        compression is performed onto the manikin's chest region,        wherein the at least one location of compression is detected by        the plurality of contact sensors; and    -   determining whether the chest compression of the CPR training        session is performed on a desired area based on the at least one        location of compression.

In the above-described method, determining comprises comparing the atleast one location of compression against a predetermined pattern ofcompression locations.

The above-described methods comprise one or more of the followingfeatures:

-   -   wherein the compression pad comprises at least one force sensor        housed within the housing, and    -   wherein the plurality of contact sensors is provided within the        housing along a perimeter of the housing such that the plurality        of contact sensors generally surround the at least one force        sensor.

The above-described methods comprise one or more of the followingfeatures:

-   -   wherein the housing comprises a top cover and a bottom cover,        wherein the compression pad comprises a flexible PCB placed        between the top cover and the bottom cover,    -   wherein the plurality of contact sensors comprises a plurality        of conductive patches and further comprises a plurality of sets        of conductive patterns formed on the PCB, and    -   wherein the compression pad is configured such that the at least        one location of compression is detected when one or more of the        plurality of conductive patches contact at least one set of        conductive patterns by the chest compression.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are provided to illustrate examples and embodimentsdescribed herein and are not intended to limit the scope of theinvention.

FIG. 1 illustrates a CPR training using a manikin.

FIG. 2 illustrates components of a CPR training system according to anembodiment.

FIG. 3 illustrates a compression pad and a breathing module under theskin of a manikin.

FIG. 4 illustrates CPR training using a CPR training system according toan embodiment.

FIG. 5 illustrates an exploded view of a compression pad according to anembodiment.

FIG. 6A is a bottom view of a PCB of the compression pad according to anembodiment.

FIG. 6B is a top view of the PCB of the compression pad according to anembodiment.

FIG. 7 illustrates thenar and hypothenar regions of a human hand.

FIG. 8A illustrates a bottom view of a top cover of the compression pad.

FIG. 8B is a top view of a bottom of the compression pad according to anembodiment.

FIG. 8C illustrates a perspective view of the compression pad accordingto an embodiment.

FIG. 9 illustrates a cross-section of the compression pad taken alongline 9-9 of FIG. 8C.

FIG. 10A illustrates deforming about longitudinal grooves formed on thetop cover.

FIG. 10B illustrates the top cover deforming about lateral groovesformed on the top cover.

FIG. 11A illustrates a cross-section of the compression pad taken alongline 9-9 of FIG. 8C.

FIG. 11B illustrates a cross-section of the compression pad of FIG. 11Awith force.

FIG. 11C illustrates a cross-section of a compression pad according toan embodiment.

FIG. 12A illustrates a breathing module according to an embodiment.

FIG. 12B illustrates a pressure sensor aligned with a lung bagconnector.

FIG. 12C illustrates a bottom view of the air pressure sensor of FIG.12B

FIG. 12D illustrates a top side view of the lung bag connector of FIG.12B.

FIG. 13 illustrates a breathing module installation kit according to anembodiment.

FIGS. 14A-14E illustrate installing the breathing module according to anembodiment.

FIG. 15 illustrates a data processing module according to an embodiment.

FIGS. 16A-16B illustrate side views of the data processing module ofFIG. 15.

FIG. 17 illustrates a CPR training procedure according to an embodiment.

FIG. 18 illustrates a procedure for chest compression moduleinitialization.

FIG. 19 illustrates signals of consecutive compressions according to anembodiment.

FIG. 20 illustrates processing of signals from consecutive compressionsof FIG. 19.

FIG. 21 illustrates force and displacement signals of consecutivecompressions of FIG. 19.

FIG. 22 illustrates correlating compression force and depth according toan embodiment.

FIG. 23 illustrates a procedure for initializing breathing moduleaccording to an embodiment.

FIG. 24 illustrates correlating air pressure and volume according to anembodiment.

FIG. 25 illustrates a procedure for evaluating compressions during a CPRtraining session.

FIG. 26 illustrates compression peaks and evaluation thereof accordingto an embodiment.

FIG. 27 illustrates a procedure for evaluating breathings during a CPRtraining session.

FIG. 28 illustrates breathing peaks and evaluating breathings accordingto an embodiment.

FIGS. 29-31 illustrate tables of condition for CPR evaluating accordingto embodiments.

FIGS. 32-34 illustrate force signals and air pressure signals of CPRtraining sequences.

FIGS. 35-38 illustrate a user interface for feedback to a user during aCPR training session.

FIG. 39 illustrates a summary of a single user's performance of CPRtraining session.

FIG. 40 illustrates a user interface showing progress of multiple users'CPR training sessions.

FIG. 41 illustrates a user interface showing a summary of multipleusers' CPR performance.

FIG. 42 illustrates a report for a CPR training session for a singleuser.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will now be described with reference to theaccompanying drawings. The terminology used in the description presentedherein is not intended to be interpreted in any limited or restrictivemanner, simply because it is being utilized in conjunction with adetailed description of certain specific embodiments of the invention.

CPR Guidelines

To perform CPR effectively, it is important to follow suggested CPRguidelines, such as those provided by the American Heart Association(AHA). AHA guidelines specify various criteria regarding the sequence ofchest compressions and rescue breathing (i.e., respiration or providingrescue breaths), the depth of the chest compressions, the rate of chestcompressions, etc. According to the AHA guidelines, each compressionshould be at least 2 inches deep and delivered at a rate of 100-120compressions per minute. After 30 compressions, a rescuer should providetwo rescue breathings. Each breath should be a normal breath for therescuer and delivered over 1 second while looking for the victims chestto rise and return to providing chest compressions. A total of twobreaths should be given to the patient and then the rescuer shouldimmediately start chest compressions again. The cycle of 30 compressionsand two rescue breathings should be continued until the professionalrescuers arrive.

CPR Training

CPR training is useful to teach students how to safely and effectivelyperform CPR. During CPR training, students may practice chestcompressions and rescue breathing on manikins, as shown in FIG. 1.Typically, a CPR training manikin has a torso assembly and a headassembly with oral and/or nasal cavities (not shown). The oral and/ornasal cavities may be connected to a lung bag which corresponds to ahuman lung. Students perform chest compressions on the torso assemblyand rescue breathings into the oral and/or nasal cavities. Accordingly,the students may practice CPR on the manikins according to the AHAguidelines.

Manikins with Integrated Sensors

Some manikins included sensors integrated with their body that monitorchest compressions and rescue breathings. These sensor-equipped manikinsdetect depths of chest compressions, breathing volumes and other aspectsof CPR training performance and provide feedback to students andinstructors. For example, some manikins use photoelectric sensors formonitoring displacement of the manikin chest during chest compressionsand flow sensors for monitoring the volume of air input into the lungbag during rescue breathings. Other manikins may not be equipped withsuch sensors. These no-sensor manikins are unable to provide feedbackregarding CPR performance.

CPR Training System

FIG. 2 illustrates components of a CPR training system according toembodiments of the invention. The CPR training system 10 includes amanikin 20, sensor modules and a data processing module 18. Inembodiments, the sensor modules include a compression pad 12 and abreathing module 14. The manikin 20 anatomically represents a humanupper body upon which CPR chest compressions and rescue breathings areto be performed. The compression pad 12 is for placing on the chest ofthe manikin 20 and sensing chest compressions performed on the manikin20. The breathing module 14 is for sensing rescue breathings performedon the manikin 20. The data processing module 18 collects and processesthe data collected from the sensor modules. Optionally, the CPR trainingsystem 10 includes an external computing device 30 that communicateswith the data processing module 18.

Manikin

In embodiments, the manikin 20 provides a torso assembly 204 including arib cage frame 220, although not limited thereto. The manikin 20 mayinclude an anatomical representation of the sternum region 222 having along, narrow and flat shape. In some embodiments, the manikin 20 mayhave markings indicating where the user's hands should be positioned tocorrectly perform chest compressions. In some embodiments, a spring orcompression damper may support an underside of the sternum region 222 toprovide compression and rebounding properties to the torso assembly 204.In embodiments, the manikin 20 is a no-sensor manikin although notlimited thereto. The manikin 20 has a head assembly 202 that includesopen oral and nasal airways 210, 212 which can be fluidly connected to alung bag 214. In the illustrated embodiment of FIG. 3, the torsoassembly 204 includes a manikin skin 216 that is overlaid onto the ribcage frame 220 and removable to expose the rib cage frame 220 and ribcage frame supports 221. In embodiments, the manikin skin 216 isflexible, elastic, and pliable similar to human skin. In someembodiments, the manikin skin 216 is not removable from the torsoassembly 204.

Chest Compression Module

In embodiments, the chest compression module 12 is also referred to as acompression pad and is to be placed over the chest region of the manikin20 where a user's hands are to be positioned to correctly perform chestcompressions. The compression pad 12 detects chest compressioncharacteristics to determine whether the user is correctly performingchest compressions. The chest compression characteristics include one ormore of compression position, compression depth, compression force,compression rate and compression acceleration although not limitedthereto.

Breathing Module

In embodiments, the breathing module 14 includes an air pressure sensor16 and a lung bag 214. The air pressure sensor 16 is fluidly andair-tightly connected to the lung bag 214. The air pressure sensor 16measures the air pressure within the lung bag 214. The air pressure isused to compute the volume of air blown into the lung bag 214 ultimatelyto determine whether the user is correctly performing rescue breathingson the manikin 20. In embodiments, the lung bag 214 is a one-time use ordisposable bag although not limited thereto.

Data Processing Module

In embodiments, the data processing module is a special purposecomputing device 18 connected to the compression pad 12 and thebreathing module 14. The data processing module 18 includes at least oneprocessor, a memory, and circuitry for communication and otherfunctions. The data processing module 18 processes data provided by thecompression pad 12 and the breathing module 14. In some embodiments, thedata processing module is implemented with software installed in ageneral purpose computer or computing device, as opposed to the specialpurpose computing device 18.

External Computing Device

In embodiments, the data processing module 18 transmits certainprocessed data to the external computing device 30 for the purpose offurther processing the data and presenting performance of CPR practices.In embodiments, the external computing device 30 includes a display uponwhich the user may be provided with immediate and real-time feedbackregarding the user's CPR performance.

Software

In embodiments, one or more software modules are stored and run on thedata processing module 18 for processing data collected from the sensormodules. In embodiments, additional software is stored and run on theexternal computing device 30 which allows the user to review feedbackregarding the user's CPR performance.

CPR Training Procedure

In embodiments, the CPR training includes the steps of installingcomponents, initializing sensor modules and CPR training sessions. TheCPR training according to embodiments of the invention may skip one ormore of these steps and may include some additional steps.

Installation of Components

To perform CPR training sessions, components of the CPR training system10 are assembled and installed. In embodiments, the compression pad 12and breathing module 14 are placed at desired locations of the manikin20 and connected to the data processing module 18.

Compression Pad Under the Skin

Referring to FIG. 3, the skin 216 is lifted or removed from the torsoassembly 204 of the manikin 20, and the compression pad 12 is placedover the chest or sternum region 222. Thereafter, the skin 216 is placedover the compression pad 12 such that the compression pad 12 ispositioned under the skin 216 of the manikin 20. For manikins where thetorso assembly does not include a removable skin, the compression pad 12may be positioned on the outer surface of the torso assembly at aposition over the sternum region.

Aligning Compression Pad

In embodiments, the center of the compression pad 12 is aligned with thecenter of the chest or sternum region 222 in view of markings providedon the manikin 20. Further, in embodiments, the compression pad 12 isplaced over the sternum region 222 such that the lengthwise direction ofthe compression pad 12 is aligned with the lengthwise direction of thesternum region 222.

Attaching Compression Pad

In embodiments, the compression pad 12 is attached to the sternum region222 using a film adhesive, Velcro or other appropriate means such thatthe compression pad 12 does not move relative to the torso assembly 204when chest compressions are performed.

Breathing Module Sandwiched Between Skin and Compression Pad

In embodiments, the breathing module 14 is installed such that the airpressure sensor 16 is connected to the lung bag 214 which is alsoconnected to the manikin's airways. In embodiments, the lung bag 21 isplaced over the compression pad 12 before the lifted or removed skin 216is placed down such that at least a portion of the lung bag 21 isinterposed between the compression pad 12 and the skin 216. FIG. 3illustrates an embodiment in which the lung bag 214 of the breathingmodule is positioned over the compression pad 12. The removable skin 216is then fastened to the manikin 20 such that the lung bag 214 and thecompression pad 12 are sandwiched between the removable skin 216 and therib cage frame 220. In other embodiments, the lung bag 214 may bepositioned outside the torso assembly 204 such that no portion of thelung bag 214 is sandwiched between the compression pad 12 and the skin216.

Initializing Sensor Modules

In embodiments, the compression module 12 and breathing module 14 arecalibrated and initialized prior to CPR training sessions. Thecompression module 12 is initialized according to chest compressionresponse characteristics of the particular manikin 20 upon which thecompression module 12 is fitted. Similarly, the breathing module 14 isinitialized according to volume-pressure relationship of the particularlung bag 214 to which the air pressure sensor 16 is connected.

Conducting CPR Training Session

In embodiments as shown in FIG. 4, after the compression pad 12 andbreathing module 14 are calibrated and initialized, a user can start aCPR training session to receive feedback regarding the user's CPR.During the training session, the CPR training system 10 monitors andanalyzes the signals from the compression pad 12 and the breathingmodule 14 to evaluate the user's performing of chest compressions andrescue breathing.

Evaluating Chest Compressions

In embodiments, the CPR training system 10 determines and evaluates thecompression depth of chest compressions being performed during the CPRtraining session based on the relationship between the compression depthand the compression force for the manikin's unique compression responsecharacteristic that was determined during the initialization process.The CPR training system also evaluates a compression rate during the CPRtraining session.

Evaluating Breathings

In embodiments, the CPR training system 10 evaluates the rescuebreathings performed during the CPR training session based on theformula or correlation representing the manikin's unique breathingcharacteristic determined in the initializing of the breathing module.

CPR Training Session Feedback

In embodiments, the CPR training system 10 determines whether anidentified compression is too strong, good, or too weak by comparing its(maximum) compression depth with a range of desirable compressiondepths. In embodiments, the CPR training system 10 also determineswhether the user performs compressions too fast, too slow, or at adesirable rate in view of a desirable compression rate. In embodiments,the CPR training system 10 also determines whether a rescue breathing istoo strong, good, or too weak by comparing the breathing volume with arange of desirable breathing volumes. In embodiments, the CPR trainingsystem provides feedback of CPR training performance in real time.

Feedback to Student or User

In embodiments, the feedback from the CPR training system 10 may bedisplayed on a user interface of the external computing device 30. Theexternal computing device 30 may have a user interface that displaysfeedback regarding the user's performance during and after the CPRtraining session.

Monitoring Multiple Training Sessions Performed Concomitantly

In embodiments, the external computing device 30 may be used to monitorthe performance of multiple users simultaneously. That is, an instructormay utilize the external computing device 30 to monitor one or more CPRtraining sessions. Further, data from CPR training sessions may be savedand reviewed at a later time.

Layers of Compression Pad

FIG. 5 illustrates the compression pad 12 according to embodiments ofthe invention. The compression pad 12 includes layers that are stackedupon each other. The compression pad 12 includes a top cover 104, abottom cover 106 and a printed circuit board (PCB) 48. The top cover 104has an outer surface 122 and an inner surface 124 (i.e., the surfacefacing the bottom cover 106). The bottom cover 106 has an inner surface126 (i.e., the surface facing the top cover 104) and an outer surface128. The PCB 48 is positioned between the top cover 104 and the bottomcover 106. The PCB 48 is enclosed by the top and bottom covers 104, 106.

Flexible and Deformable Covers

In embodiments, each of the top and bottom covers 104, 106 of thecompression pad 12 have a thin flexible and deformable constructionformed of elastomeric material such as latex or silicone rubber. Theflexible and deformable construction of the covers enable that overallthe compression pad 12 is configured to flex and deform when a pressureor force is applied thereto during chest compressions. Accordingly, thecompression pad 12 can conform to the shape of the chest region of themanikin 20 when the compression pad 12 placed there and skin 216 isfastened to the manikin 20. The flexibility and thickness of thecompression pad 12 does not block, obstruct or impede the fitting andfastening of the skin 216 to the manikin 20.

Shape of Compression Pad

Referring to FIG. 5, the top and bottom covers 104, 106 aresubstantially flat and planar. In embodiments, the top and bottom covers104, 106 also have a generally rounded rectangular hourglass shape withthe length in the X axis that is greater that the width in the Y axis.The narrower middle region provided by the hourglass shape providesincreased flexibility at the narrower middle region relative to widerregions. The compression pad 12 is not limited to a rounded rectangularhourglass shape and may have a variety of shapes. In embodiments, thelength is from about 13 to about 20 cm, and the width is from 8-14 cm.In some embodiments, the length is about 15-17 cm, and the width isabout 10-12 cm.

Size of Compression Pad

Proper hand placement for performing CPR chest compressions requires theheel of the user's hand to be positioned over the sternum region 222.Accordingly, the compression pad 12 is configured in a size and shapethat aligns with and covers the sternum region 222. In some embodiments,the compression pad 12 may have a universal size that allows the CPRtraining system 10 to be fitted to a variety of manikin sizes (infant,baby, junior, adult, etc.).

Interior Cavity of Bottom Cover

The bottom cover 106 has an interior cavity 108 that is recessed intothe inner surface 126 of the bottom cover 106. The interior cavity 108has a shape that corresponds to the PCB 48. The interior cavity 108 maybe defined by an outer sidewall 112 of the bottom cover 106. In someembodiments, the PCB 48 is attached to the inner surface 126 of thebottom cover 106 by an adhesive.

Top and Bottom Covers Attached to Each Other

The top cover 104 is attached to the bottom cover 106 along the outersidewall 112. The top and bottom covers 104, 106 are attached to eachother by adhesive, bonding or other fastening techniques such that theflexible PCB 48 is enclosed between the top and bottom covers 104, 106.In embodiments, the top and bottom covers 104, 106 may have a connectionarrangement, such as but not limited to, snap-fit connectors, alignmentholes and pins, bosses, etc. which may be used to align and attach thetop and bottom covers 104, 106 together.

Flexible PCB

As illustrated in FIG. 5, in embodiments, the PCB 48 includes a thinfilm substrate, circuitry printed on the film, chips, sensors and othercomponents of the compression pad 12. The sensors include anaccelerometer 40, two force sensors (or pressure sensors) 42, 44 andmultiple contact sensors 46. In embodiments, the thin film substrate isformed from layers of thin film material that is flexible orsemi-flexible so as to be able to bend without short circuiting ordegradation of the connections with the sensors or mounted components.FIG. 6A is a view of an underside 116 of the flexible PCB 48. FIG. 6B isa view of a top side 118 of the PCB 48.

Accelerometer

In embodiments, the accelerometer 40 is positioned on the underside 116of the PCB 48 facing the bottom cover 106. The accelerometer 40 ispositioned near the center 107 of the PCB 48 but offset a distance fromthe center 107 of the PCB 48. The accelerometer 40 is in the form of achip based on MEMS technology and may include capacitive, piezoelectric,Hall-effect and semiconductor type accelerometers. Once assembled in thecompression pad, the accelerometer chip 40 protrudes from the undersideof the PCB 48 and received in a recess formed into the bottom cover 106,which avoids or reduces direct impact of compression force onto thechip.

Measurements by Accelerometer

During chest compressions, the accelerometer 40 measures theacceleration of the compression pad 12 or the acceleration applied tothe compression pad 12 in the Z axis (i.e., depth direction orcompression/rebound direction of the rib cage frame 220 of the manikin20). The acceleration in the Z direction can be used to compute thedepth of compression. In some embodiments, the accelerometer 40 alsomeasures the acceleration along the X axis (i.e., the height directionof the manikin 20 and the lengthwise direction of the compression pad12) and the Y-axis (i.e., the width direction of the manikin 20 and thewidthwise direction of the compression pad 12). The acceleration in theX axis and the Y axis may be used to calculate the angle of chestcompression force. In some embodiments, the accelerometer 40 may includean assembly of one or more accelerometers such that separateaccelerometers measure the acceleration along a single axis.

Force Sensors

As shown in FIGS. 6A and 6B, in embodiments, the compression pad 12includes two force sensors 42, 44, although not limited to two sensors.The force sensors 42, 44 senses the pressure or force applied to thecompression pad 12 when chest compressions are performed. The forcesensors 42, 44 generate a force signal representing the force orpressure applied to the compression pad 12. It should be understood toone of ordinary skill in the art that the term pressure or force may beused interchangeably throughout the disclosure to describe a forceapplied to the compression pad 12.

Configuration of Force Sensors

In embodiments, each force sensor 42, 44 has a top surface facing thetop cover 104 and a bottom surface facing the bottom cover 106. Inembodiments, the top and bottom surfaces are made of a rigid material toreceive force or pressure in a direction passing the two surfaces. Inembodiments, the top and bottom surfaces are substantially flat. Inembodiments, the force sensors 42, 44 are single-element piezo-electricor piezo-resistive pressure sensors, although not limited thereto.

Force Sensor Locations

As shown in FIGS. 6A and 6B, in embodiments, the two force sensors 42,44 are positioned along the longitudinal direction or the X axis of thePCB 48 with a distance therebetween. In embodiments, each force sensor42, 44 is equidistantly offset a distance from the center 107 of the PCB48 along the X axis. In embodiments, the force sensors 42, 44 may bespaced apart from each other by a distance that is substantially equalto the distance between the thenar region 96 and hypothenar region 98 ofan average-sized adult human measured near the base of the hand, asillustrated in FIG. 7. In embodiments, the distance between the centersof the force sensors 42, 44 is about 4.5, 5.0, 5.5, 6.0, 6.5 and 7.5 cm.The distance between the centers of the force sensors 42, 44 is in arange formed by two chosen from the numbers listed in the immediatelyprevious sentence. Accordingly, the force sensors 42, 44 are positionedon the PCB 48 such that the force sensors 42, 44 are aligned with thethenar and hypothenar regions 96, 98 of the user's hand when the user'shand is properly placed over the compression pad.

Through-Holes for Force Sensors

As shown in FIG. 6B, in embodiments, the PCB 48 has two through-holes140 that correspond to the force sensors 42, 44 such that the forcesensors 42, 44 are aligned with the through-holes 140. The force sensors42, 44 are connected to terminals 136 formed on the underside of the PCB48 via connecting arms 134, and extend through the through-holes 140from an underside 116 of the PCB 48 to the topside 118 of the PCB 48. Asthe force sensors 42, 44 correspond to the through-holes 140, the twothrough-holes 140 are spaced apart from each other along the X axis bythe same distance of the force sensors 42, 44 as discussed in theforegoing paragraph. In some embodiments, no through-holes are formed inthe PCB 42, and the force sensors 42, 44 are formed onto the undersideor topside of the thin film substrate of the PCB 48. When nothrough-holes are formed, no circuitry or circuit lines are formed onthe thin film substrate where the force sensors 42, 44 are to contact.

Contact Sensors

In embodiments, as in FIG. 8A, the compression pad 12 has a plurality ofcontact sensors 46 that detect areas or locations of the compression pad12 to which the force of chest compressions is applied. The detection isused for determining whether the user's hands are properly positioned onthe manikin 20 and the compression pad 12. In embodiments, the contactsensors 46 are comprised of a plurality of flexible and electricallyconductive contact patches 50 formed on the top cover 104 and exposedelectrical traces 52, 54, 56, 58 formed on the PCB 48. In embodiments,the contact sensors 46 (patches and electrical traces) generallysurround the force sensors 42, 44 when viewed in the Z axis and arearranged along the perimeter or outer edges of the compression pad 12.In embodiments, the contact sensors 46 (patches and electrical traces)are arranged along both lengthwise edges (i.e., generally along the Xaxis) and both widthwise edges (i.e., generally along the Y axis) of thecompression pad 12.

Contact Patches and Exposed Electrical Traces Correspond

In embodiments, as shown in FIG. 8A, the contact patches 50 arepositioned on the inner surface 124 of the top cover 104. As shown inFIG. 6B, the four sets of exposed electrical traces 52, 54, 56, 58 areformed on the top side of the PCB 48 and face the contact patches. Inthe illustrated embodiment, each set of the exposed electrical traces52, 54, 56, 58 extends along an edge of the PCB 48. In embodiments, thecontact patches 50 are positioned over and aligned with the exposedelectrical traces 52, 54, 56, 58. As shown in FIG. 9 (a cross-sectiontaken along the line 9-9 in FIG. 8C), each contact patch 50 ispositioned immediately over part of one set of the exposed electricaltraces 52, 54, 56, 58. Although not illustrated, multiple contactpatches 50 along one edge of the top cover 104 correspond to theextension of one set of the exposed electrical traces 52, 54, 56, 58along one edge of the PCB 48.

Contact Patches

As illustrated in FIG. 9, in embodiments, each contact patch 50 is aconductive material piece inserted into a recess formed on the perimeterof the top cover 104. Each contact patch 50 is not electricallyconnected to any circuit or to any of the other contact patches 50. Thetop surface of the contact patch 50 is at a level slightly lower thanthe perimeter surface of the top cover 104 (slightly higher than theperimeter surface in FIG. 9) such that the contact patch 50 would notcontact its corresponding set of the exposed electrical traces of thePCB 48 without applying force onto the top cover 104 of the compressionpad 12. The contact patches 50 may be formed from a conductiveelastomeric material such as conductive carbon or silicone rubber. Inother embodiments, a conductive film can be formed on an outer contactsurface of the contact patches 50 that are not made of a conductivematerial.

Detecting Force or Pressure by Contact Sensors

Each set of the exposed electrical traces 52, 54, 56, 58 includesmultiple conductive lines (contact patterns) 70, 72 that are printed onthe upper side of the PCB 48 such that they run generally parallel toeach other with a gap and not electrically connected with each other(open circuit). When external force is applied to the compression pad 12over contact patches 50, at least one contact patch 50 contacts at leasttwo of the multiple conductive lines 70, 72 of its corresponding set. Asa result, the at least two conductive lines become electricallyconnected with each other via the at least one contact patch 50 and forma closed circuit, which is detected as an indication of the contactbetween contact patch and exposed electrical traces.

Determining Hand Position

Accordingly, when the user's hand applies force onto the top cover 104of the compression pad 12, one or more of the contact patches 50 contacttheir corresponding set(s) of the exposed electrical traces 52, 54, 56,58 and form closed circuit(s). Depending upon which sets of the exposedelectrical traces form a closed circuit, the system may determinelocations and areas of the compression pad 12 where compression force isapplied. In embodiments, the system includes software and/or hardwarethat interprets the pattern of contacts to determine whether the user'shand is properly positioned on the compression pad 12 and/or themanikin's chest region. For example, if less than all four electricaltraces 52, 54, 56, 58 are in a closed-circuit state, that may beinterpreted as the user's hands not properly positioned over the sternumregion 222. In some embodiments, signals from the contact sensors 46 maybe cross-referenced and compared with the data from the force sensors42, 44 and/or accelerometer 40 to further indicate whether the user'shands are properly positioned on the manikin 20 and the compression pad12.

Pressing Plates and Support Plates

In embodiments, the compression pad 12 includes pressing plates 142 thattransfer the force applied to the compression pad 12 to the forcesensors 42, 44. Referring to FIGS. 5 and 8A, the pressing plates 142 areprovided on the inner surface 124 of the top cover 104. Similarly, inFIGS. 5 and 8B, support plates 144 are provided on the inner surface 126of the bottom cover 106. The pressing plates 142 and support plates 144are made of a rigid material such as metal. In one embodiment, thepressing and support plates are made of stainless steel for therigidity.

Force Sensor Sandwiched Between Corresponding Set of Pressing andSupport Plates

In embodiments, as shown in FIG. 9, one pressing plate 142 is positioneddirectly above the force sensor 42 and one support plate 144 ispositioned directly below the force sensor 42 such that the force sensor42 is positioned between the pressing plate 142 and support plate 144.Although not illustrated, the force sensor 44 is similarly positionedbetween the other set of pressing and support plates 142, 144. Further,since the pressing plates 142 and support plates 144 are positioneddirectly above and below the force sensors 42, 44, the pressing plates142 and support plates 144 are also are aligned with the thenar andhypothenar regions 96, 98 of the user's hand when the hand is properlyplaced on the compression pad 12.

Attachment of Pressing and Support Plates

In embodiments as shown in FIG. 9, the support plates 144 are positionedwithin the inner surface 126 of the bottom cover 106 such that the topsurface of the support plates 144 is flush with the inner surface 126.In other words, the outer surface 150 of the support plates 144 is levelwith the inner surface 126 of the bottom cover 106. The pressing plates142 and support plates 144 are attached to the inner surfaces 124, 126of the top and bottom covers 104, 106 by an adhesive material. In someembodiments, the pressing plates 142 and support plates 144 may bemolded into the inner surfaces 124, 126 of the top and bottom covers104, 106.

Shape of Support Plates

In embodiments, the pressing plates 142 may have a different plan shape(in the X-Y plane) than the support plates 144 of the bottom cover 106.In embodiments, the support plates 144 of the bottom cover may have ashape that accommodates the accelerometer 40, and the chips 64 that aremounted on the underside 116 of the PCB 48. The shape of the supportplates 144 also correspond with chip recesses 172 formed within theinner surface 126 of the bottom cover 106 that provide a cavity withinwhich the accelerometer 40 and the chips 64 may reside.

Size of Pressing Plates

In embodiments, as shown in FIGS. 8A to 9, each pressing plate 142 issignificantly larger than each force sensor in the X-Y plane such thatas forces applied to much wider than the force sensor in the X-Y planecan be transferred to the force sensor. On the other hand, inembodiments, each pressing plate 142 is significantly smaller than thecompression pad 12 in the X-Y plane such that the top cover 104 remainsflexible even with the hard material of the pressing plates 142.

Projection of Pressing Plate

In embodiments, as shown in FIG. 9, each pressing plate 142 has a raisedportion or projection 146 generally in its central area in the X-Y planethat protrudes in the Z axis toward its corresponding force sensor 42 or44. In embodiments, the projection 146 has a contact surface facing itscorresponding force sensor 42, and the projection 146 is sized to matchand aligned with the corresponding force sensor 42 such that the contactsurface of the projection 146 can contact as much surface of the forcesensor 42 or a layer 132 formed over the force sensor when force isapplied to the compression pad 12.

Configurations of Support Plate

In embodiments, the support plate as shown in FIGS. 8A to 9, eachsupport plate is significantly larger than each force sensor (in the X-Yplane) and substantially flat piece. Although not illustrated, eachsupport plate may include a raised portion in its central area as in thepressing plates such that the raised portion is aligned with the bottomsurface of the force sensor.

Interfaces with Force Sensor

In embodiments, as shown in FIG. 9, the pressing plate 142 does notcontact the force sensor 42 or a force sensor pad 138 placed above theforce sensor 42 when no force is applied to the compression pad 12. Whenthe force is applied to the compression pad 12, the raised portion 146of the pressing plate 142 moves downward and presses the sensor pad 138and transmits force to the force sensor 42. In embodiments, as shown inFIG. 9, the force sensors 42, 44 contact its corresponding supportplates 144 even when no force is applied to the compression pad 12. Inother embodiments, an air gap may be provided between each force sensorand corresponding support plate. In other embodiments, a material may beinserted between each force sensor and corresponding support plate.

Single Pressing Plate and Single Support Plate

Although not illustrated, in some other embodiments, the compression pad12 may include a single pressing plate (i.e., instead of two separatepressing plates 142) that transfers the downward force applied to thecompression pad 12. Such a single pressing plate may be positionedgenerally at the central area of the top cover 104 such that downwardforce applied at the top cover 104 may be detected by both force sensors42, 44. The compression pad 12 may also have only one support platesupporting two force sensors 42, 44.

Force Sensor Pad

In embodiments, as in FIGS. 5 and 9, the compression pad 12 includes aforce sensor pad 138 positioned on each force sensor 42, 44. The forcesensor pad 138 may be attached to the top surface of the force sensors42, 44 such that it faces the projection 146 of the pressing plate 142.The force sensor pad 138 has a size and shape similar to the top surfaceof the force sensor 42, 44 and to the contact surface of the projection146.

Semi-Rigid Pad

In embodiments, the force sensor pad 138 is formed of a semi-rigidmaterial such as rubber or plastic. In embodiments, the semi-rigidmaterial is softer or less rigid than the pressing plates and alsosofter or less rigid than the top surface of the force sensors. Thesemi-rigid material is not too soft or deformable such thatsubstantially all force applied to the force sensor pad can betransferred to the force sensors. The semi-rigid material allows theforce sensor pad 138 to distribute the downward force applied by theprojections 146 laterally across the top surface of the force sensors42, 44, as opposed to just a corner of a projection 146 contacting theforce sensors 42, 44 when the pressing plates 142 descends downward atan angle relative to the force sensor pad 138.

Gap Between Pad and Projection

In embodiments, a small gap is provided between the force sensor pad 138and the projections 146 of the pressing plate 142 when no downward forceis applied to the compression pad 12. In other embodiments, the forcesensor pad 138 and the projections 146 may be in slight contact when nodownward force is applied to the compression pad 12.

Grooves and Ribs

In embodiments, the top cover 104 of the compression pad 12 includes aplurality of grooves and protrusions on its inner surface 124. Referringto FIG. 8A, longitudinal grooves 162 and lateral grooves 164 are formedon the inner surface 124 of the top cover 104. Ribs 166 are definedbetween these grooves as portions that are raised relative to thegrooves. The structure of ribs and grooves increases localizedflexibility and bending of the top cover 104 at locations within the topcover 104 where increased flexibility is desired. That is, the locationand amount of bending or deformation of the top cover 104 may be variedby positioning the grooves and ribs at specific portions within the topcover 104.

Longitudinal Grooves

In embodiments, as illustrated in FIGS. 8A and 10A, the longitudinalgrooves 162 extend generally linearly in the lengthwise direction or inthe X axis. The longitudinal grooves 162 are incrementally spaced fromthe center 105 of the top cover 104 and extend longitudinally betweenboth pressing plates 142. Longitudinal grooves 162 also extend along thelongitudinal edges of both pressing plates 142 in the top cover 104.

Lateral Grooves

The lateral grooves 164 extend generally linearly in the widthwisedirection or in the Y axis. The lateral grooves 164 are incrementallyspaced from the center 105 of the top cover 104 between both pressingplates 142. The lateral grooves 164 extend laterally between theoutermost longitudinal grooves 162. Lateral grooves 164 are alsopositioned between the outermost lateral edges of both pressing plates142 between each pressing plate 142 and the contact sensors 50.

Making Grooves. Size and Shape

The longitudinal and lateral grooves 162, 164 may be molded into the topcover 104 during the molding process for forming the top cover 104.Alternatively, the longitudinal and lateral grooves 162, 164 may be cutor removed from the top cover 104. The depth, width and length of eachrespective groove 162, 164 affect the amount of bending of the top cover104. In the illustrated embodiment, the depths and widths of eachlongitudinal and lateral groove 162, 164 is substantially equal. In someembodiments, the depths and widths of the longitudinal and lateralgrooves may vary to provide increased or decreased bending of the topcover 104 at different locations. In embodiments, the top cover 102 isnot limited to grooves in longitudinal and lateral direction. Groovesmay extend in any direction. Similarly, the grooves are not limited toany size, shape or geometry and may vary according to the desiredbending characteristics of the compression pad 12. In the illustratedembodiments, no grooves and ribs are provided in the bottom cover 106.In some embodiments, however, the bottom cover 106 may have grooves andribs that are similar to those discussed herein.

More Bending with Grooves

The grooves 162, 164 are recessed into the inner surface 124 of the topcover 104, which results in reduction of the thickness of the top cover104 within the recessed longitudinal and lateral grooves 162, 164. Thereduced thickness in the grooves enables the grooves acting as an axisfor localized bending or rotating of the top cover 104. FIG. 10Aillustrates the outer edges of the top cover 104 bending about thelongitudinal grooves 162. FIG. 10B illustrates the top cover 104 beingbent in half about the lateral grooves 164.

More Bending Facilitates Lateral Transfer of Force

FIG. 11A illustrates a cross-section of the top cover 104 taken by aplane passing line 9-9 of FIG. 8C when no force is applied to thecompression pad 12. FIG. 11B illustrates the same cross-section whendownward force is applied in the Z axis. With the grooves 162 betweenribs 166, the top cover 104 bend in multiplicity about the extensions ofthe grooves 162 (into the drawing sheet) as the grooves 162 act as localbending or rotational axes. With the localized bending in multiplicity,the amount of deformation of the top cover 104 is more than it wouldhave when no such grooves and ribs are provided in the top cover 104.FIG. 11C illustrates an embodiment without grooves or ribs in the topcover 104, in which the top cover 104 deforms generally in the immediateregion where the downward force is applied. As a result, the pressingplates 142 may not contact the force sensor 42. More deformation of thetop cover as in FIG. 11B causes transfer of the downward force inlateral directions (i.e., in X-Y plane) toward the pressing plate 142such that the pressing plate 142 contact the force sensors 42, 44despite the force not being applied immediately over the pressing plate142. In embodiments, the deformation occurs over a wider area of the topcover 104 which includes the region of the top cover 104 surrounding thepressing plates 142.

Smaller Size Force Sensors

The greater and wider deformation provided by the structure of groovesand ribs ensures that the pressing plates 142 transfer the downwardforce to the force sensors 42, 44 despite not being applied directlyover the pressing plates 142 or force sensors 42, 44. Thus, thecompression pad 12 can have small size force sensors 42, 44 compared tothe size of the compression pad 12. In embodiments, with the structureof grooves and ribs, the ratio of the area of the top cover of thecompression pad to the total area of the top surfaces of the all forcesensors is 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170,180, 190, 200, 210, 220, 230, 240 or 250. In embodiments, the ratio isin a range formed by two selected from the numbers listed in theimmediately preceding sentence. In some embodiments, the ratio of thearea of the compression pad to the total area of the top surfaces of theforce sensors is from 70 to 140, from 80 to 120.

Grooves Closely Spaced Between Pressing Plates

In embodiments, the width (along the Y axis) of each longitudinal groove162 located between the two pressing plates 142 is smaller than thewidth of each longitudinal groove 162 located in other areas of the topcover 102. In embodiments, the width (along the Y axis) of ribs formedbetween two immediately neighboring longitudinal grooves 162 locatedbetween the pressing plates 142 is smaller than the width (along the Yaxis) of ribs formed between two immediately neighboring longitudinalgroove 162 in other areas of the top cover 102. Similarly, the width ofribs (along the X axis) formed between two immediately neighboringlateral groove 164 located between the pressing plates 142 is smallerthan the width of ribs formed between two immediately neighboringlateral groove 164 in other areas of the top cover 102. Accordingly, theflexibility of the top cover 104 between the pressing plates 142 isgreater (i.e., where there are more grooves per unit area) than in areasof the top cover 104 outside of the area between the pressing plates142.

Pressing Plates Surrounded by Grooves

In embodiments, as shown in FIG. 8A, the pressing plates 142 areentirely surrounded by the longitudinal and lateral grooves 162, 164when viewed along the Z axis. In some embodiments, the grooves surroundeach pressing plate 142 at least partially when viewed in the samedirection. Having the pressing plates 142 at least partially surroundedby the grooves 162, 164 provides the top cover 104 with flexibility thatallows the pressing plates 142 to move downward and transfer thedownward force laterally to the force sensors 42, 44 during chestcompressions.

Chest Compression Module Conforms to Manikin

The increased flexibility and bending of the top cover 104 provided bygrooves 162, 164 also allow the compression pad 12 to conform to theshape of the rib cage frame 220 such that the compression pad 12 is lessvisible and does not protrude from under the skin 216 when thecompression pad 12 is placed under the skin. Protrusion through theremovable skin 216 would conspicuously indicate the position of thecompression pad 12 on the manikin 20 which is undesirable for teachingproper hand position for performing CPR. In embodiments, when thecompression pad 12 is positioned over the sternum region 222 of themanikin 20, outer portions of the compression pad 12 may extend beyondthe sternum region 222 into the left-side and right-side rib sections224, 226. In embodiments, the left-side or right-side rib sections 224,226 may have a curved or contoured shape. As such, when the removableskin 216 is positioned over the compression pad 12, the outermostlongitudinal grooves 162 allow the top cover 104 and the compression pad12 to conform to the contours of the left-side or right-side ribsections 224, 226.

Ribs for Varying Levels of Flexibility

As shown in FIG. 8A, ribs 166 are formed on the inner surface 124 of thetop cover 104 between the longitudinal grooves 162 and lateral grooves164. Some ribs 166 are not defined or surrounded entirely betweengrooves and are connected to perimeter of the top cover 104. Inembodiments, the surface of the ribs 166 facing the PCB 48 is flush withthe inner surface 124. While some ribs are entirely surrounded bygrooves to increase flexibility of the top cover 104, other ribsconnected to the perimeter of the top cover are provided to reduceflexibility and deformation where desired. Also, for varying levels offlexibility, some ribs are wider and longer than others. In theillustrated embodiments, the ribs 166 have a rectangular prism orcylindrical shape. However, in other embodiments, the ribs 166 may haveany shape, size, or depth and may extend in any direction.

Chip Recesses

In embodiments, as shown in FIGS. 8B and 9, chip recesses 172 are formedinto the inner surface 126 of the bottom cover 106. The chip recesses172 are positioned in portions of the bottom cover 106 that correspondto the positions of the accelerometer 40 and the chips 64 on the PCB 48.

Protective Cushion

In embodiments, the chips 64 may have a protective cushion (not shown)that surrounds and protects the chips 64 from the sidewalls of the chiprecesses 172. The protective cushion may be formed from a foam or spongematerial. When the compression pad 12 deforms due to chest compressions,the protective cushion inhibits or prevents contact between the chips 64and the sidewalls of the chip recesses 172. The protective cushionprotects the chips 64 from possible damage.

Air Pressure Sensor

Referring to FIGS. 2 and 12A-12D, the breathing module 14 includes anair pressure sensor 16 and a lung bag 214. The air pressure sensor 16has a housing 80 that is attached to the lead wire 62. The housing 80has an male connector 82 protruding from the housing 80. An air pressureinlet opening 86 is positioned within the male connector 82 and extendsinto the housing 80 through which the air pressure sensor 16 detects airpressure. In embodiments, the male connector 82 has a retaining flange84 that extends radially outward from the outer surface of the airpressure inlet fitting 82.

Lung Bag Connector

In embodiments, the air pressure sensor 16 is connected to the lung bag214 by a lung bag connector 250. The lung bag connector 250 provides anair-tight interface such that the air pressure sensor 16 may beconnected to one-time use or disposable lung bags. The lung bagconnector 250 has a base portion 252, a female connector 254, a recessedflange 258, an adhesive film 268 and a liner 270 covering the adhesivefilm. The lung bag connector 250 may be formed from a flexible materialsuch as plastic or rubber. The lung bag connector 250 is flexible suchthat the base portion 252 conforms to the inflated and deflated shapesof the lung bag 214. The female connector 254 extends from the baseportion 252 on a first side and the adhesive film 268 is formed to thebase portion 252 on a second side that is opposite the first side. Thefemale connection 252 includes a hole 256 that has a size and shape thatcorresponds to the male connector 82. The recessed flange 258 ispositioned within the hole 256 and has a size and shape that correspondsto the retaining flange 84 of the male connector 82 such that therecessed flange 258 receives and engages with the retaining flange 84when the male connector 82 and female connector 254 mate.

Connecting Air Pressure Sensor to Lung Bag Connector

In embodiments, the air pressure sensor 16 is connected to the lung bagconnector 250 by inserting the male connector 82 into the femaleconnector 254. The retaining flange 84 of the male connector 82 engagesthe recessed flange 258 of the female connector 254 such that the airpressure sensor 16 is securely fastened to the lung bag connector 250.The hole 256 and the male connector 82 form an air-tight seal. Inembodiments, the lung bag connector 250 has a male connector, and theair pressure sensor 16 has a corresponding female connector.

Breathing Module Installation Kit

FIG. 13 illustrates a breathing module installation kit 300 that allowsthe air pressure sensor 16 to be connected to one-time use or disposablelung bags 316. The breathing module installation kit 300 includes a holepunch 310, a hole punch guide template 320, a seal 330 and a lung bagconnector 250. The hole punch 310 is a tool for punching holes into adisposable lung bag 316. The hole punch 310 punches a hole that issimilar in size to the hole 256 of the lung bag connector 250.

Hole Punch Guide Template

In embodiments, the hole punch guide template 320 is a paper templatehaving a marking 322 which is used to indicate where the hole punch 310should be positioned to punch a hole through the disposable lung bag316. In embodiments, the hole punch guide template 320 is foldable orfolded along a folding line such that two sections divided by thefolding line can at least in part overlap with each other. The holepunch guide template 320 is used to ensure that the user does not puncha hole too close to the edge of the disposable lung bag 316 such thatthe lung bag connector 250 cannot be attached and/or an air tight sealcannot be maintained. That is, the marking 322 is positioned on the holepunch guide template 320 such that the hole punched through thedisposable lung bag 316 is positioned at least the distance between thehole 256 and the outer edge of the base portion 252 of the lung bagconnector 250.

Seal

In embodiments, the seal 330 is used to cover and seal the hole on oneside (wall) of the disposable lung bag 316 since a hole will be punchedthrough two opposite sides (walls) of the disposable lung bag 316. Theseal 330 may have a self-stick adhesive layer that is covered by aremovable cover or wrapper.

Installing Breathing Module

In FIGS. 14A-14E, the steps for installing the air pressure sensor 16 tothe disposable lung bags 316 are illustrated.

Aligning Hole Punch Guide Template with Lung Bag

First, referring to FIG. 14A, the hole punch guide template 320 ispositioned on a corner of the disposable lung bag 316. In embodiments,the edges of the disposable lung bag 316 are aligned with edges and/orfolds on the hole punch guide template 320 although not limited thereto.In embodiments, the template 320 has a first section and a secondsection folded along a folding line such that the two sections overlapwith each other. The template is aligned such that the first section ison one side of the lung bag 316 and the second section is on the otherside of the lung bag 316 while the folding line between the two sectionsare aligned with an edge of the lung bag 316.

Punching Two Holes on Opposite Sides of Lung Bag

Subsequently, referring to FIG. 14B, the hole punch 310 is aligned withthe marking 322 of the hole punch guide template 320 and a hole ispunched through the disposable lung bag 316 and the hole punch guidetemplate 320. In embodiments, the hole punch 310 punches a hole on eachof the opposite sides of the lung bag 316. As a result, two holes arepunched on the lung bag 316: one through the side contacting the firstsection of the template 320 and the other through the side contactingthe second section of the template.

Sealing One Hole

As in FIG. 14C, the seal 330 is attached onto the disposable lung bag316, covering and sealing one hole formed on one side of the disposablelung bag 316. The self-stick adhesive layer fastens the seal to thedisposable lung bag 316 and ensures an air tight seal is formed.

Connecting Lung Bag Connector

As in FIG. 14D, the lung bag connector 250 is attached to the disposablelung bag 316 and positioned over the hole on the other side of thedisposable lung bag 316 (i.e., opposite the hole covered by the seal330). The liner 270 of the lung bag connector 250 is removed to exposeadhesive film 268, and the lung bag connector 250 is fastened to thedisposable lung bag 316 by the adhesive film 268. When attaching thelung bag connector 250 onto the lung bag 316, the hole 256 of the lungbag connector 250 is aligned with the hole formed though the side of thedisposable lung bag 316 such that the female connector 254 of the lungbag connector 250 provides a fluid pathway into the disposable lung bag316.

Connecting Air Pressure Sensor and Lung Bag Connector

Subsequently, as in FIG. 14E, the air pressure sensor 16 is connected tothe lung bag connector 250 by inserting the male connector 82 into thehole 256 of the female connector 254 of the lung bag connector 250. Theair pressure sensor 16 is securely fastened to the lung bag connector250 by the retaining flange 84 of the male connector 82 and the recessedflange 258 of the female connector 254. Accordingly, the air pressuresensor 16 is in fluid communication with the interior of the disposablelung bag 316 and may measure the air pressure within the disposable lungbag 316.

Connection to Data Processing Module

In embodiments, the compression pad 12 and breathing module 14 areconnected to the data processing module 18 via lead wires 60, 62 orwirelessly such that each of the compression pad 12 and the breathingmodule 14 can send data obtained from their sensors immediately andreal-time to the data processing module. In such embodiments, each ofthe compression pad 12 and the breathing module 14 has circuitry forwirelessly communication with the data processing module 18 or otherdevices. In the compression pad 12, wireless circuits may be integratedinto the PCB 48 and positioned within a connector portion 115 of thecompression pad 12, as shown in FIG. 8C. The wireless module ispositioned outside of the force detecting region of the compression pad12 such that the wireless module is not disturbed or damaged by chestcompressions.

Data Processing Module Connected to Other Devices

In embodiments, the data processing module 18 immediately processes thedata from the compression pad 12 and the breathing module 14 as soon asthey are received. The data processing module 18 stores the data atleast temporarily. The data processing module 18 immediately transmitsat least part of processing results and other data to the externalcomputing device 30 or other devices to which the data processing module18 is connected via wire or wireless connections. In embodiments, thedata processing module 18 may include a wireless transmitter/receiver towirelessly communicate with the external computing device 30 via Wi-Fi,Bluetooth, BLE, Infrared Data Association or other wirelesscommunication standards. In some embodiments, the data processing module18 can be omitted, and the compression pad 12 and breathing module 14are directly connected to the external computing device 30 or otherdevices via wired or wireless connection.

External Computing Device

Referring to FIG. 4, the external computing device 30 is in the form ofa mobile tablet computer. In embodiments, the external computing device30 receives data from the data processing module and provides real-timefeedback about the user's CPR performance. Further, the externalcomputing device 30 also stores the user's CPR performance such that aninstructor may review the user's CPR performance at a later time. Inembodiments, the external computing device 30 may be connected tomultiple CPR training systems 10, i.e., multiple data processing modules18 at the same time such that an instructor may simultaneously monitorthe CPR training performance of multiple users. In some embodiments, theexternal computing device 30 may communicate with a database managementserver (not shown) and upload the CPR performance of users to acloud-based server such that aggregate information regarding CPRperformance may be stored and analyzed. It should be understood to oneof ordinary skill in the art that the external computing device 30 isnot limited to a mobile tablet computer and may include other computingdevices such as medical monitors, computers integrated into the manikinor medical training equipment, etc.

CPR Training Procedure

FIG. 17 illustrates a CPR training procedure according to embodiments ofthe invention. The CPR training procedure starts with providing a CPRtraining system at step 1710. In embodiments, the CPR training system 10includes a manikin 20, a compression module 12, a breathing module 14,and a data processing module 18. Subsequently, the compression module 12and breathing module 14 are assembled and installed on the manikin atstep 1720. FIG. 4 illustrates the CPR training system installed on themanikin. Next, at step 1730, the compression module 12 and breathingmodule 14 are initialized or calibrated. Afterwards, at step 1740, CPRtraining sessions are conducted using the CPR training system 10.

Providing and Installing CPR Training System

In embodiments, the CPR training system includes one or more featuresdiscussed above with reference to FIGS. 1-16. In embodiments, thecompression module 12 in the form of a pad is placed over the manikin'schest region as discussed above. In embodiments, the breathing module 13is assembled and its lung bag 316 is placed over the compression pad 12.In embodiments where the manikin has a removable skin, the compressionmodule 12 and the lung bag 316 are arranged under the skin. Inembodiments, the compression module 12 and breathing module 14 areconnected to the data processing module 18 or another device for dataprocessing.

Initializing Compression Module

Referring to FIG. 18, in embodiments, initialization of the compressionmodule 12 begins with performing a predetermined number of initializingor reference chest compressions at step 1810. During the initializingcompressions, the accelerometer 40 of the compression pad 12 detectsacceleration at step 1820. Also, the force sensors 42, 44 of thecompression pad 12 detect force at step 1820. Using accelerationsignals, the compression depths are computed at step 1830. Force signalsand compression depths computed from acceleration signals at each giventime are processed to provide correlation or a formula between thecompression depths and the compression force at step 1840. The formulaor correlation represents the manikin's unique compressioncharacteristics. In embodiments, the signal processing is performed bythe data processing module 18. In embodiments, the external computingdevice 30 has an application providing user interfaces to guide the stepof initialization process.

Force and Acceleration Signals

FIG. 19 illustrates force signals and acceleration signalssimultaneously obtained during the initializing compressions at step1820 or any CPR training sessions. In embodiments, the force signalspresented in FIG. 19 are combined signals from the two force sensors 42,44. For example, signals from two piezoelectric sensors can be added oraveraged to produce a single force signal. Each peak of the forcesignals represents a single compression made to the manikin's chestregion.

Monitoring Force Sensor Signal

The CPR training system obtains signals from the force sensor of thechest compression module as the user practices CPR to the manikin duringthe CPR training session. When two or more force sensors are used in thechest compression module, signals from the two or more force sensors canbe processed to generate a single force signal. For example, signalsfrom two piezoelectric sensors can be added or averaged to produce asingle force signal for identifying and evaluating a compression duringa CPR training session.

Processing Acceleration Signals to Provide Displacement Signals

At step 1830 of FIG. 18, the acceleration signals are processed tocompute displacement of the compression pad 12, which representscompression depths of the initializing compressions. In embodiments, theacceleration signals are integrated once to provide velocity signals,and integrated twice to provide displacement signals. FIG. 20illustrates acceleration signals and the corresponding velocity anddisplacement signals.

Peak Detection from Displacement Signals

In embodiments, the displacement signals are further processed toidentify peaks in the displacement signals. Each peak of thedisplacement signal corresponds to a single compression. Thedisplacement signals of FIG. 20 include peaks D1, D2, D3 identified bythe additional processing.

Corresponding Peaks of Force Signals and Displacement Signals

In embodiments, the force signals are processed to detect peaks. Thepeaks of the force signals and the peaks of the displacement signalsrelate to compressions made during the initializing compressions.Accordingly, in embodiments, each compression corresponds to one peak ofthe force signals and one peak of the displacement signal. Referring toFIG. 21, the peaks P1, P2 and P3 of the force signals respectivelycorresponds to the peaks D1, D2, D3 of the displacement signals.

Correlating Compression Depth and Compression Force

In embodiments, peak values of the force signals and displacementsignals are obtained and correlated. Each peak value of the forcesignals is paired with a peak value of the displacement signals thatcorresponds in time. Thus, the paired peak values of the force anddisplacement signals are of the same compression. In some embodiments,pairing peak values of the force and displacement signals continue forall compressions made during the initializing compressions. Inembodiments, the paired peak values, i.e., compression force and depthare plotted. FIG. 22 plots two of such initializing compressions forManikin A 2210 and for Manikin B 2220. For each manikin, in embodiments,the CPR training system identifies to a linear graph 2210, 2220representing the relationship between compression force and compressiondepth using a linear regression analysis. In other embodiments, the CPRtraining system utilizes various other approaches to identify a formulaor correlation between compression force and compression depth of theinitializing compressions.

Initializing Compression Module for Every Manikin

In embodiments, the initialization of the compression module 12 isperformed for every manikin. Each manikin is constructed differently,primarily due to differences in the materials and construction of thetorso assembly and springs therein. Thus, chest compressioncharacteristics may differ from manikin to manikin. Manikins made by thesame manufacturer and even same model of manikins are not exceptionsunless their chest compression characteristics are tested andquality-controlled. As illustrated in FIG. 22, Manikin A 2210 and forManikin B 2220 have different compression characteristics, i.e.,different correlation between the compression force and compressiondepth.

Initializing Compression Module for Every Training Floor

In embodiments, the initialization of the compression module 12 isperformed for every change of training locations or floors. The sensingof the compression module 12 may depend on the rigidity of floor uponwhich the manikin is placed.

Initializing Breathing Module

FIG. 23 illustrates a procedure for initializing the breathing module14. In embodiments, initialization of the breathing module 14 beginswith performing a predetermined number of initializing or referencebreathings at step 2310. The air pressure sensor 16 detects air pressurein the lung bag 214 during these initializing breathings. The airpressure signals from the air pressure sensor 16 are processed to obtainair pressure values corresponding to each breathing made during theinitializing breathings at step 2320. Then, the air pressure values arecorrelated to breathing volumes of the initializing breathings at step2330.

Initializing Breathings

The initializing breathings include blowing a known volume of air intothe oral and/or nasal cavities of the manikin for sending the knownvolume of air to the lung bag 214. In some embodiments, the same knownvolume of air is blown multiple times. In some embodiments, varyingvolumes of air are blown into the lung bag 214 connected to the manikin20. In other embodiments, a generally the same volume of air is blowninto the lung bag 214 multiple times even if the exact volume is notknown.

Detecting Peaks of Air Pressure Signals for Initializing Breathings

In embodiments, air pressure signals are processed to identify peaksrepresenting individual breathings of the initializing breathings. TheCPR training system obtains the peak values, each of which correspondsto the maximum volume of air blown into the lung bag 214 in eachbreathing made during the initializing breathings.

Correlating Breathing Volume and Air Pressure of Initializing Breathings

At step 2330, the CPR training system correlates breathing volume andair pressure values from the initializing breathings. In embodimentswhere the same or generally the same volume of air is blown multipletimes, the air pressure values and the known volume of air are plotted.FIG. 24 plots two of such initializing breathings into Manikin A forLung bag LB1 and Lung bag LB2. For each lung bag, in embodiments, theCPR training system identifies to a linear graph 2410, 2420 representingthe relationship between the breathing volume and air pressure using alinear regression analysis. As illustrated, the linear graphs 2410, 2420passes the origin point in the plot as data for the linear regressionanalysis are limited to the same breathing volume. In other embodiments,the CPR training system may utilizes various other approaches toidentify a formula or correlation between the breathing volume and airpressure from the initializing breathings.

Initializing Breathing Module for Every Lung Bag

In embodiments, the initialization of the breathing module 14 isperformed for every lung bag 214. Lung bags may have differentvolume-pressure characteristics which may also vary between lung bagmanufacturers, variances between identical manikins, variances in sensorinstallations, etc.

Batch or Real-Time Data Processing for Initializing

In embodiments, processing of signals and correlating values can beperformed after the completion of the initializing compressions orinitializing breathings. In the alternative, processing of signals andcorrelating values can be performed real time while the initializingcompressions or initializing breathings are being performed.

Conducting a CPR Training Session

After the completion of the initialization of the compression module 12and breathing module 14, CPR training sessions are conducted using theCPR training system. In embodiments, the CPR training system monitorssensor signals from the compression module 12 and the breathing module14, evaluates each compression and breathing of the CPR trainingsession, and provides real-time feedback to the user.

CPR Sequence

Typically, a CPR training session includes a sequence of five cycles ofcompressions and breathings, in which each cycle consists of thirty (30)compressions and two (2) breathings. In some embodiments, the CPRtraining system provides a step-by-step guidance CPR training sessionprompting the user for the sequence. In other embodiments, no suchguidance is provided, and the user is expected to perform the CPRsequence by herself.

Evaluating Compressions

FIG. 25 is a procedure for evaluating compressions during CPR trainingsessions. In embodiments, the force sensors 42, 44 detect force and thecompression pad sends force signals to the data processing module 18 atstep 2510. The CPR training system detects peaks of the force signalsand obtains peak values in the force signals at step 2520. For eachpeak, the CPR training system computes or determines a compression depthat step 2530, using the formula or correlation previously obtained fromthe initialization of the compression pad 12.

Acceleration Signals for Evaluating Compressions

In embodiments, while acceleration signals are used during theinitialization stage, acceleration signals are not used during CPRtraining sessions for obtaining the compression depth. In theseembodiments, force signals are used for the compression depth generallyto avoid delays in integrating acceleration signals twice and also toavoid circuitry for or delays in removing high frequency noises. Inother embodiments, acceleration signals may be used for determining thecompression depth (displacement) as in the initialization stage. In suchembodiments, the initialization of the compression module can beomitted. In embodiments, the CPR training system may utilizeacceleration signals to determine directions of chest displacement.

Detecting Peaks in Force Signals

FIG. 26 illustrates a process of detecting peaks in force signals fromthe force sensors and evaluating the peaks to confirm a compression. Inembodiments, the CPR training system may repeatedly monitor the forcesignals at a frequency (significantly) shorter than a typical chestcompression frequency of CPR training sessions. Based on the monitoring,the CPR training system determines whether the force signal is greateror smaller than a predetermined reference value or a compressionthreshold. In embodiments, the CPR training system utilizes a peakdetection technique to detect the maximum point of a peak real timebefore the signals form the next peak. One of ordinary skill in the artshould understand that peak detection techniques are available and canbe used in the CPR training system. In embodiments, the CPR trainingsystem repeatedly updates the maximum value within a given time windowfrom T₁-T_(f) to T₁. At T1, when there is no value higher than theprevious maximum value at T₁-T_(f) during the time window, the maximumvalue of Peak A corresponds to the maximum depth of the particularcompression at step 2651.

Determining Compression Depth

Once the peak value is obtained, the compression depth is computed atstep 2653. In embodiments, the formula or correlation obtained from theinitialization stage for the particular manikin is used to determine orcompute the compression depth. In embodiments, even if signals from theaccelerometer 40 are available, acceleration signals are not referencedfor determining the compression depth. Subsequently, the CPR trainingsystem evaluates each compression using the computed compression depthat step 2655. In embodiments, the compression depth is compared againsta predetermined range of desirable compression depths to determinewhether the particular compression is too strong, good or too weak.

Real-Time Feedback

In embodiments, the CPR training system provides the evaluation resultof each compression depth to the user real time, desirably prior to theuser's next compression. For example, referring to FIG. 26, theevaluation for Peak A is provided to the user before compression forPeak B is initiated or completed. For adjusting timing of providing anevaluation result of compressions during an on-going CPR trainingsession, the CPR training system may adjust length of the time windowT_(f) for identifying a peak (a compression) in the force signals. Insome embodiments, the CPR training system is configured to provide anevaluation of the current compression within ¼ of the desirable timeinterval between two consecutive compressions. Considering that adesirable compression rate is about 100 to 120 compressions per minute,the CPR training system may be configured to initiate a process ofcomputing compression depth within at least 0.15 sec. since a peakappears in the force signal. In other embodiments of the invention, theCPR training system may be configured to detect a peak with a timewindow having 0.05 sec.

Evaluating Compression Rate

In embodiments, the CPR training system calculates a rate ofcompressions using time intervals between two consecutive compressionsthat are determined based on peak detection. The CPR training systemdetermines whether the user performs compressions too fast, too slow orat a desirable rate by comparing the computed rate against apredetermined desirable compression rate.

Evaluating Compression Position

In embodiments, the CPR training system determines locations and areasof the compression pad onto which the compression force is applied usingthe contact sensors 46. The CPR training system determined if thelocations and areas are proper by comparing the detected locations andareas against a predetermined pattern of contact. Compression positioncan be determined and evaluated using sensor signals from the contactsensors of the chest compression module.

Various Contact Patterns

In some embodiments, when no contact is detected by the contact sensorsbut a force signal indicative of a compression is sensed by the forcesensor, the CPR training system determines that a contact forcompression is made only at a central portion of the compression pad 12.In embodiments, when a contact is detected by the contact sensor but theforce signal is too weak to confirm a compression, the CPR trainingsystem determines that the user missed a compression. In embodiments,when a contact is detected by the contact sensor and the force signal isstrong enough to confirm a compression, the CPR training systemdetermines that a compression is made on a peripheral area of thecompression pad 12.

Evaluating Recoil Between Compressions

A desirable CPR procedure requires a full rebound or recoil of the chestbetween compressions. A full recoil between compressions is importantbecause it will ensure re-filling of the heart chambers betweencompressions. In embodiments, the CPR training system can determinewhether a desirable recoil between two consecutive compressions hasoccurred. For example, when a chest displacement becomes smaller than apredetermined reference between two consecutive compressions, the CPRtraining system determines that a desirable recoil has been made.

Evaluating Breathings

FIG. 27 illustrates a procedure for evaluating breathings during CPRtraining sessions. The procedure for evaluating breathings starts withobtaining air pressure signals during a CPR training session at step2710. The CPR training system identifies breathings based on patterns(peaks) in the air pressure signals at step 2720. For each of theidentified breathings, the CPR training system computes a breathingvolume at step 2730. The formula determined in initializing of thebreathing module can be used to compute the breathing volume during theCPR training session. The CPR training system evaluates individualbreathings using the computed breathing volume at step 2740. Thecomputed breathing volume is compared with one or more predeterminedreference volumes for evaluating the identified breathing. The CPRtraining system presents to the user the evaluation result in real time,desirably prior to the initiation of the next breathing, such that theuser can adjust her next breathing based on the real-time feedback.

Detecting Peaks of Air Pressure Signals for Training Breathings

FIG. 28 illustrates a process for detecting peaks in air pressuresignals and evaluating the peaks to confirm a breathing. In embodiments,the CPR training system may repeatedly monitors the air pressure signalsat a frequency (significantly) shorter than a typical breathingfrequency of CPR training sessions. Based on the monitoring, the CPRtraining system determines whether the air pressure signal is greater orsmaller than a predetermined reference value or a breathing threshold.In embodiments, the CPR training system utilizes a peak detectiontechnique to detect the maximum point of a peak real time before thesignals form the next peak. One of ordinary skill in the art shouldunderstand that peak detection techniques are available and can be usedin the CPR training system. In embodiments, the CPR training systemrepeatedly updates the maximum value of the air pressure signal 2810while monitoring the air pressure signal 2810. When there has been noupdate of a maximum since a peak appears in the air pressure signals fora given time duration T_(a), the CPR training system uses the peak valueas representing the maximum air pressure of a breathing. For example, atT₂, when the given time duration of T_(a) has passed since a peak atT₂-T_(a) in the air pressure signal 2810, the CPR training sessiondetermines the peak at T₂-T_(a) indicates a breathing performed on themanikin.

Evaluating Breathing Volume

In embodiments, once a breathing is confirmed during a CPR trainingsession, the CPR training system initiates a process for evaluating theconfirmed breathing. First, at step 2851, the maximum value of detectedpeak C is obtained. Subsequently, at step 2853, the CPR training systemcomputes or determines the volume of the confirmed breathing using themaximum value based on the formula or correlation between the volume andthe air pressure obtained in the initialization stage. Subsequently, atstep 2855, the CPR training system evaluates if the breathing is toostrong, good or too week by comparing the breathing volume with apredetermined range of desirable breathing volume. In other embodiments,the CPR training system may compare the air pressure representing eachof the breathing peaks with a reference value representing initializingbreathings received for initializing the breathing modules. For example,in a case when the CPR training system requested five moderatebreathings assuming the same volume of initializing breathings, the CPRtraining system may determine that an identified breathing has adesirable breathing volume when the air pressure of the breathing iswithin a range from an air pressure representing the five moderatebreathings.

Providing Evaluation of Breathings

In embodiments, the CPR training system provides the evaluation resultof each breathing prior to the user's next breathing. For example, theCPR training system initiates computing breathing volume correspondingto the peak C at T₂ to provide evaluation result of the breathingcorresponding to the peak C before the user performs the next breathing(peak D). Providing evaluation result of a breathing prior to anupcoming breathing is desirable because the user can receive evaluationon a current (or a most recent) breathing before the user performsanother breathing after the current breathing. For adjusting timing ofproviding evaluation result of breathing during on-going CPR trainingsession, the CPR training system may adjust length of the time windowT_(a) for identifying a peak (breathing) in the air pressure signals. Insome embodiments, the CPR training system is configured to provideevaluation of the current breathing within ¼ of the desirable timeinterval between two consecutive breathings. Considering that it isdesirable to perform rescue breathing at a rate of ten to twelve breathsper minute (for adults) the CPR training system may be configured toinitiate a process of computing breathing volume within at least about1.25 second since a peak appears in the air pressure signal.

Cross-Talk Between Force Signals and Air Pressure Signals

In embodiments, compressions are detected and evaluated based on forcesignals from the force sensors 44, 46 within the compression pad 12.Breathings are detected and evaluated based on air pressure signals fromthe breathing module 14. Further in embodiments, the compression pad 12and the lung bag 214 are installed closely inside the manikin 20. Inmany embodiments, the lung bag 214 is placed over the compression pad 12under the manikin's skin. Since the force sensors and the air pressuresensor detect generally the same nature of physical properties, forceand pressure, compressions may generate air pressure signals andbreathings may also generate force signals. Further, a breathing intothe lung bag 214 may generate a contact signal from the contact sensors46.

Determining Between Compressions and Breathings Needed

During CPR training sessions, compressions and breathings are repeated.Sometimes both the air pressure sensor and the force sensors generatesignals for a single compression or a single breathing. In embodiments,the CPR training system processes the force signals, contact signalsand/or air pressure signals to determine whether the user performs acompression or a breathing.

Determining Based on Force Signals and Air Pressure Signals

FIG. 29 provides a table of conditions for determining breathing orcompression based on force signals and air pressure signals obtained atthe same time. In embodiments, when the force signal indicates a forceweaker than a reference force and the air pressure signal indicates abreathing volume less than a reference volume (2910), the CPR trainingsystem determines that the user has performed neither a compression nora breathing, i.e., idle. In FIG. 34, the signals of time window 3460provide an example of determining neither a compression nor a breathingbased on low signals. When the force signal indicates a force greaterthan a predetermined reference and the air pressure signal indicates abreathing volume less a reference volume (2920), the CPR training systemdetermines that the user is performing a compression. In embodiments,when the force signal indicates a force weaker than a reference forceand the air pressure signal indicates a breathing volume greater than areference volume (2930), the CPR training system determines that theuser is performing breathing. In determining a compression, nocompression, a breathing or no breathing, the CPR training systemrepeatedly obtains the force signal and air pressure signal at a givenfrequency and compares the signal values against their threshold values.

When Both Force Signals and Air Pressure Signals are Strong

When the force signal is enough to confirm a compression and airpressure signals are also enough to confirm a breathing (2940), the CPRtraining system may not determine the user action or may consideradditional information for the determination of the current user action.In some embodiments, the CPR training system determines that the userperforms a compression given that compressions significantly outnumberbreathings in the CPR sequence. In other embodiments, the CPR trainingsystem determines the user action further based on the time taken fromthe peak of the immediately previous action to the current action. Ifthe time is shorter than a predetermined reference time, the systemdetermines that the user has performed a compression, vice versa. Inother embodiments, the CPR training system determines the user actionfurther in view of the number of immediately previous consecutivecompressions or the number of immediately previous consecutivebreathings, assuming that the user follows the predetermined CPRsequence.

Determining Based on Air Pressure Signals and Contact Sensor Signals

FIG. 30 provides a table of conditions for determining breathing andcompression based on air pressure signals and context sensor signalsobtained at the same time. In embodiments, when the contact sensorsignals are not at a level to confirm a contact and the air pressuresignals are not at a level to confirm a breathing (3010), the CPRtraining system determines that the user has not performed a compressionor a breathing. In embodiments, when the contact sensor signals indicatea contact and the air pressure signals indicate a breathing volume lessa reference volume (3020), the CPR training system determines that theuser is performing a compression. In embodiments, when the contactsensor signals do not indicate and the air pressure signal indicates abreathing volume greater than a reference volume (3030), the CPRtraining system determines that the user is performing breathing.

When Both Contact Sensor Signals and Air Pressure Signals are Strong

When contact sensor signals are enough to confirm a contact and airpressure signals are also enough to confirm a breathing (3040), the CPRtraining system may not determine the user action or may consideradditional information for the determination. In some embodiments, theCPR training system determines that the user performs a compressiongiven that compressions significantly outnumber breathings in the CPRsequence. In other embodiments, the CPR training system determines theuser action further based on the time taken from the peak of theimmediately previous action to the current action. If the time isshorter than a predetermined reference time, the system determines thatthe user has performed a compression, vice versa. In other embodiments,the CPR training system determines the user action further in view ofthe number of immediately previous consecutive compressions or thenumber of immediately previous consecutive breathings, assuming that theuser follows the predetermined CPR sequence.

Determining in View of Known Last Action

In embodiments, the CPR training system determines whether the userperforms a compression or a breathing based on a force signal and an airpressure signal obtained at a given time and further based on theimmediately preceding action (last action) of the user that the CPRtraining system has determined or knows. FIG. 31 provides a table ofconditions for determining the user action of breathing or compressionin view of the immediately preceding action of the user.

Last Action Being Compression

In case the last action was a compression, the CPR training systemdetermines that the user has performed a compression when the airpressure signal is smaller than a breathing threshold or not at a levelto confirm a breathing and further the force signal is greater than acompression threshold or enough to confirm a compression (3120). In casethe last action was a compression, the CPR training system determinesthat the user has performed a breathing, i.e., a transition fromcompression to breathing when the air pressure signal is greater thanthe breathing threshold or enough to confirm a breathing, and furtherthe force signal is smaller than the compression threshold or not at alevel to confirm a compression (3130).

Last Action Being Breathing

Still referring to FIG. 31, in case the last action was a breathing, theCPR training system determines that the user has performed a breathingat this time when the air pressure signal is enough to confirm abreathing and further force signal is not at a level to confirm acompression (3160). In case the last action was a breathing, when theair pressure signal is not at a level to confirm a breathing and furtherthe force signal is enough to confirm a compression (3170), the CPRtraining system determines that the user has performed a compression atthis time, i.e., a transition from breathing to compression.

Last Action Being Either Compression or Breathing

In embodiments, in case neither the air pressure signal nor force signalreaches their predetermined levels to confirm a compression or abreathing (3110 and 3150), the CPR training system determines that theuser is not performing a compression or breathing, i.e., an idle periodregardless of the last action of the user. In case the last action was acompression or a breathing, when the air pressure signal is enough toconfirm a breathing, and further the force signal is also enough toconfirm a compression (3140 and 3180), this time the CPR training systemdoes not determine the current user action or refer to additionalinformation for determination of the user action.

Determining with Reference to Additional Information

In some embodiments, the CPR training system determines that the userperforms a compression, given that compressions significantly outnumberbreathings in the CPR sequence. In other embodiments, the CPR trainingsystem determines the user action further based on the time taken fromthe peak of the immediately previous action to the current action. Ifthe time is shorter than a predetermined reference time, the systemdetermines that the user has performed a compression, vice versa. Inother embodiments, the CPR training system determines the user actionfurther in view of the number of immediately previous consecutivecompressions or the number of immediately previous consecutivebreathings, assuming that the user follows the predetermined CPRsequence. In FIG. 33, the signals of time window 3360 provide examplesof determining a compression based on immediately previous consecutivecompressions or based on the time taken to the current action from theimmediately previous peak confirmed for either a compression orbreathing.

Interpreting Signal Profiles of FIG. 32

FIG. 32 illustrates force signals 3210 and air pressure signals 3230obtained during a user's performance of a CPR training session. Inembodiments, the CPR training system detects peaks of force signals thatare greater than a predetermined compression threshold 3220 foridentifying or confirming compressions. The CPR training system alsodetects air peaks of pressure signals that are greater than apredetermined breathing threshold 3240 for identifying or confirmingbreathings. Referring to FIG. 32, the CPR training system determines anidle period 3250 (no compression and no breathing) at times between T₃₂₁to T₃₂₂ when both the force signal and air pressure signal are belowtheir thresholds 3220, 3240 respectively. In embodiments, the CPRtraining system determines a breathing at T₃₂₂ because the air pressuresignal turns from smaller to greater than the breathing threshold 3240that occurs after the immediately previous determination (or consecutiveprevious determinations including the last one) of no breathing or airpressure signal being smaller than the breathing threshold 3240 andfurther because the force signal remains smaller than the compressionthreshold 3220 since the immediately previous determination of nobreathing that occurred at a time prior to T₃₂₂ (or between T₃₂₁ andT₃₂₂). In other embodiments, the CPR training system determines atransition from compression to breathing because the idle period 3250after the last confirmed compression is longer than a predeterminedvalue, e.g., 2 seconds. This is because typically it takes time for theuser to change posture for the transition. The CPR training systemdetermines a breathing at a time after T₃₂₂ when the air pressure signalis greater than the breathing threshold 3240 and the force signal issmaller than the compression threshold 3220. The CPR training systemdetermines an idle state (neither compression nor breathing) at timesbetween T₃₂₃ and T₃₂₄ when neither the force signal nor the air pressuresignal goes beyond their respective threshold 3220, 3240. The CPRtraining system determines a transition from breathing to compression atT₃₂₃ because the air pressure signal is smaller than the breathingthreshold 3240 and the force signal turns from smaller to greater thanthe compression threshold 3220 after the last determination (or afterthe consecutive determinations including the last one) of no compressionor force signal being smaller than the compression threshold 3220.

Compressions Beginning Before Complete Deflation of Lung Bag

FIG. 33 illustrates force signals and air pressure signals during a CPRtraining session. The air pressure signals in the period between T₃₃₂and T₃₃₃ includes a sharp peak that represents a single breathing. Afterthe sharp peak, the air pressure signal in this period decreases at aslow rate, which represents that no breathing follows immediately afterthe single breathing for a while and the lung bag is being deflatedslowly as the air is being spontaneously discharged. It is notable thatno significant force signals are detected during this period from T₃₃₂to T₃₃₃. At or after T₃₃₃, the force signals reach or exceed thecompression threshold 3320, which can be confirmed as compressions.Also, at or after T₃₃₃ in the period 3360, the air pressure signalsfluctuate such that at times the air pressure signal is greater than thebreathing threshold, which could potentially represent breathings.

Determining Compression Regardless of Strong Air Pressure Signals

In embodiments, the CPR training system determines a compression even ifthe air pressure signal at a given time is greater than the breathingthreshold 3340 when it interprets fluctuation of the air pressuresignals as caused by the user's compressions before complete dischargeof air from the air bag or while a significant amount of the air isremaining in the lung bag. This may occur when the spontaneous dischargeof air from the lung bag is slow or when the user's transition from thecompression to breathing takes place very quickly. In some embodiments,the CPR training system ignores the fluctuating air pressure signals ofthe period 3360 of FIG. 33 when the last determined action is breathingand further the subsequent fluctuation in the air pressure signal issubstantially synchronized. For example, the CPR training system maydetermine substantial synchronization of the force signals and airpressure signals when the frequency of the air pressure signalfluctuation is substantially similar to the frequency of force signalfluctuation. Alternatively, time for peak value, time for valley valueor time for passing threshold value can be used in lieu of the frequencyfor determining substantial synchronization. In some embodiments, theCPR training system ignores the fluctuating air pressure signals of theperiod 3360 when the last determined action is breathing and furthertime or frequency of the air pressure fluctuation is shorter than apredetermined time or frequency for a breathing. In some embodiments,the CPR training system determines a transition from breathing tocompression when the idle period after the last confirmed breathing islonger than a predetermined value.

Breathing Skipped

FIG. 34 illustrates force signals and air pressure signals during a CPRtraining session, in which a user performs two sets of compressions andskips a set of breathing between the two sets of compressions. Inembodiments, the CPR training system determines the two sets ofcompressions from the force signals. Given that force signals or airpressure signals are smaller than their threshold values, inembodiments, the CPR training system determines that no compression orbreathing occurred between the two sets of compressions.

Ignoring Signals When Anticipating Particular Action

When it is known to the CPR training system that the user will perform acompression, the CPR training system may not utilize certain airpressure signals or force signals for evaluating the user's action tothe manikin. In embodiments, the CPR training system anticipates theimmediately next or current user action based on the CPR trainingguidelines. In embodiments, the CPR training system is programmed toselect a CPR training sequence before performing a CPR training session.In such embodiments, during the CPR training session, the CPR trainingsystem anticipates the next or current action of the user and ignoresair pressure signals and utilizes force signals and other signals foranalysis of the next or current user action when a compression isanticipated based on the sequence. When the anticipated action is abreathing, the CPR training system ignores (does not rely on) forcesignals and utilizes air pressure signals for analysis of the useraction.

Ignoring Force Signals When Anticipating Breathings

When it is known to the CPR training system that the user will perform abreathing, the CPR training system may not utilize signals from theaccelerator, the force sensor, or the contact sensors to evaluate theuser's action. For example, in a situation when the user is guided orexpected to perform a breathing, the CPR training system utilizes sensorsignals from the air pressure sensor for evaluating expected breathingswhile not monitoring or utilizing sensor signals from the compressionpad. As such, while the CPR training system can obtain signals from allsensors installed inside the manikin during the CPR training session,the CPR training system may not access or utilize signals from allsensors for evaluating compressions/breathings of CPR when the CPRtraining system has information regarding expected action of the userbased on a user selection or a progress of CPR procedure.

Determining and Evaluating User Actions

In embodiments, the CPR training system determines a compression, nocompression, a breathing or no breathing based on signal inputs fromvarious sensors and processing of the signal inputs using previouslyobtained data such as from initialization stage. In embodiments, thedata processing module 18 performs these processes and determinations ofthe CPR training system using at least one processor and software storedin the data processing module 18. In embodiments, the CPR trainingsystem evaluates user actions during CPR training sessions. Inembodiments, the data processing module 18 performs these evaluationsusing at least one processor and software stored therein. In otherembodiments, the processing, determination and evaluation may beperformed at least in part by the compression module 12 and/or thebreathing module 14 with at least one processor. In other embodiments,the processing, determination and evaluation may be performed at leastin part by the external computing device 30 or other computing devices.

Feedbacks During CPR Training Session

FIG. 35 illustrates a user interface for providing feedback during anongoing CPR training session. In embodiments, the CPR training systemprovides one or more indicators representing a progress of CPR trainingsession. As illustrated in FIG. 38, the CPR training system informs thatthe user is practicing the first one of the five scheduled cycles 3810.The CPR training system provides an indicator of compression count 3820.The CPR training system provides an indicator of real-time compressiondepth 3830. The CPR training system provides evaluation of a current(most recent) compression 3840. The CPR steering system provides anindicator of compression position 3850. FIG. 36 illustrates anotherexample of feedback provided during CPR training session. Inembodiments, the CPR training system provides a warning 3910 that themost recent compression was too strong in view of a specification ofdesirable CPR procedure. FIG. 37 illustrates another example of feedbackprovided during CPR training session. In embodiments, the CPR trainingsystem can determine whether a full recoil has been made between twoconsecutive compressions based on chest displacement between the twocompressions. When the chest displacement between the two compressionsdoes not indicate a full recoil which is represented by a chestdisplacement less than a predetermined reference, the CPR trainingsystem can provide a warning 4010. FIG. 38 illustrates a feedback fromCPR training system when sensor signals indicate an idle time periodduring CPR training session. In embodiments, the CPR training systemmeasures an idle time period of idle signals in which the sensor signalsfrom the compression pad and the sensor signals from the breathingmodules do not indicate a compression, a breathing or a contact. The CPRtraining system may inform a trainee how long the CPR training systemhas not received signals indicating a contact 4110.

Presenting CPR Training Session Results

FIG. 39 illustrates a summary of a single user's performance of CPRtraining session. In embodiments, the CPR system informs a trainee ofthe number of successful compressions and the number of successfulbreathings after completing a CPR training session. FIG. 40 illustratesa user interface showing progress of multiple users' CPR trainingsessions. FIG. 41 illustrates a user interface showing a summary ofmultiple users' performance of CPR training sessions. In embodiments,the CPR training system can simultaneously conduct multiple CPR trainingsessions for multiple users, evaluate individual actions of the multipleusers, and provide feedback regarding the multiple training sessions toa single device of a trainer who is governing the CPR training for themultiple users. FIG. 42 illustrates a report for a CPR training sessionfor a single user.

Modifications, Combinations and Subcombinations

Although the invention has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that various features and aspects of the present invention extendbeyond the specifically disclosed embodiments to other alternativeembodiments. In addition, while a number of variations have been shownand described in detail, other modifications, which are within the scopeof the invention, will be readily apparent to those of skill in the artbased upon this disclosure. It is also contemplated that variouscombinations or subcombinations of the specific features and aspects ofthe embodiments may be made and still fall within the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed invention. Thus,it is intended that the scope of the present invention herein disclosedshould not be limited by the particular disclosed embodiments describedabove, and that various changes in form and details may be made withoutdeparting from the spirit and scope of the present disclosure as setforth in the following claims.

What is claimed is:
 1. A method for a CPR training, the methodcomprising: providing a manikin comprising a frame and a removable skinfitted over the frame corresponding to a rib cage of a human body;providing a compression pad comprising a housing, at least one forcesensor, at least one acceleration sensor housed within the housing, theat least one force sensor configured to detect force applied thereto,the at least one acceleration sensor configured to detect accelerationapplied thereto; lifting or removing at least a portion of the removableskin to expose at least part of the frame; subsequently placing thecompression pad over the frame; subsequently fitting the removable skinover the frame such that the compression pad is located in a chestregion of the manikin and interposed between the frame and the removableskin; performing initializing compressions onto the chest region,wherein each initializing compression applies an initializing force andan initializing acceleration to the compression pad, wherein the atleast one force sensor detects initializing forces applied during theinitializing compressions and generates initializing force signals inresponse to the initializing compressions, wherein the at least oneacceleration sensor detects initializing accelerations applied duringthe initializing compressions and generates initializing accelerationsignals in response to the initializing compressions; processing theinitializing acceleration signals to generate initializing displacementsignals representing initializing displacements of the compression padduring the initializing compressions; processing the initializing forcesignals and the initializing displacement signals to provide adisplacement-force correlation between the initializing displacementsand the initializing forces; subsequently, performing a CPR trainingsession that comprises training compressions onto the chest region,wherein the at least one force sensor detects a training force appliedto the compression pad in response to each training compression andgenerates a training force signal corresponding to the training force;and computing a training displacement using the training force signaland the displacement-force correlation between the initializingdisplacements and the initializing forces, wherein the trainingdisplacement is not computed based on a training acceleration applied tothe compression pad during the training compressions.
 2. The method ofclaim 1, wherein the at least one force sensor comprises a first forcesensor and a second force sensor that are apart from each other withinthe housing, wherein the first and second force sensors are configuredto generate their own force signals which are processed to provide theinitializing force signals of the at least one force sensor and thetraining force signal of the at least one force sensor, wherein thecompression pad comprises a first pressing plate and a first supportplate between which the first force sensor is sandwiched, wherein thefirst pressing plate comprises a raised portion raised toward the firstforce sensor and configured to contact the first force sensor inresponse to an external pressure applied to the compression pad.
 3. Themethod of claim 1, wherein the compression pad further comprises: aprinted circuit board (PCB) enclosed within the housing; a plurality ofcontact patches provided on an inner surface of the housing, wherein theplurality of contact patches are made of an electrically conductivematerial and are not electrically connected to each other; and a contactpattern formed on the PCB, wherein the contact pattern comprises two ormore electrically separate conductive lines in close proximity with eachother and exposed toward at least part of the plurality of contactpatches, wherein each contact patch faces two or more conductive linesof the contact pattern, wherein the compression pad is configured togenerate a contact signal when one of the plurality of contact patchescontacts the two or more conductive lines of the contact pattern inresponse to an external pressure applied onto the housing.
 4. The methodof claim 1, further comprising: presenting the computed trainingdisplacement to a user who is performing the CPR training session inreal time.
 5. The method of claim 1, further comprising: comparing thecomputed training displacement against a predetermined value todetermine whether each compression of the CPR training session satisfiesa compression depth requirement; presenting a result of the comparisonin real time.
 6. The method of claim 1, further comprising: providing alung bag and an air pressure sensor connected to the lung bag andconfigured to detect air pressure within the lung bag; connecting thelung bag with a breathing cavity of the manikin such that the breathingcavity of the manikin and the lung bag are in fluid communicationtherebetween; placing the lung bag over the compression pad afterplacing the compression pad over the manikin's frame; blowing a volumeof air into the lung bag via the breathing cavity of the manikin,wherein the air pressure sensor detects air pressure within the lung bagduring the blowing and generates an initializing air pressure signal inresponse to the blowing; processing the initializing air pressure signaland the volume to provide a volume-pressure correlation between thevolume and the air pressure within the lung bag during the blowing;subsequently, performing the CPR training session that further comprisesat least one training breathing via the breathing cavity, which blowsair into the lung bag, wherein the air pressure sensor detects atraining air pressure within the lung bag during the at least onetraining breathing and generates at least one training air pressuresignal in response to the at least one training breathing; and computinga volume of air blown into the lung bag during the at least one trainingbreathing using the at least one training air pressure signal and thevolume-pressure correlation between volume and air pressure.
 7. Themethod of claim 6, wherein the CPR training session comprises thetraining compressions and the at least one training breathing, whereinthe method further comprises: when the training force detected by the atleast one force sensor is greater than a predetermined compressionthreshold, confirming performance of a training compression; and whenthe training air pressure detected by the air pressure sensor is greaterthan a predetermined breathing threshold, confirming performance of atraining breathing.
 8. The method of claim 7, wherein the CPR trainingsession involves a first instance in which the air pressure sensordetects a first air pressure greater than the predetermined breathingthreshold in response to performing the training compressions even if nobreathing is performed during the training compressions.
 9. The methodof claim 8, wherein the CPR training session involves a second instancein which the at least one force sensor detects a second force greaterthan the predetermined compression threshold in response to performingthe at least one training breathing even if no compression is performedduring the at least one training breathing.
 10. The method of claim 9,wherein upon confirming performance of a training compression, if thefirst instance follows, the method determines that a trainingcompression has been performed regardless of the first air pressuregreater than the predetermined breathing threshold.
 11. The method ofclaim 9, wherein upon confirming performance of a training breathing, ifthe second instance follows, the method determines that a trainingbreathing has been performed regardless the second force greater thanthe predetermined compression threshold.
 12. The method of claim 6,wherein the lung bag is placed over the compression pad after placingthe compression pad over the manikin's frame and before fitting theremovable skin over the frame, wherein the method does not detect thevolume of air blown into the lung bag during the at least one trainingbreathing.